Electrical wiring device and mounting means therefor



Oct. 17, 1961 H. E. RADACK 3,005,178

ELECTRICAL WIRING DEVICE AND MOUNTING MEANS THEREFOR Filed Feb. 23, 1960INVENTOR. H/QPQ V E- 7404C4 BY a/Zpcmk a 594% United States Patent3,005,178 ELECTRICAL WIRING DEVICE AND MOUNTING MEANS THEREFOR Harry E.Radack, Trenton, N.J., assignor to Circle F Mfg. Co., Trenton, N.J., acorporation of New Jersey Filed Feb. 23, 1960, Ser. No. 10,161 5 Claims.(Cl. 339-128) This invention relates to electrical wiring devices havingmounts of the type designed for snap-in engagement in supporting panels.

The invention has particular adaptability for use with rotary canopyswitches, but is not necessarily restricted to said use.

Most usually, switches of this type are mounted on a panel by insertionof a threaded nipple of the switch through an aperture of said panel.Thereafter, a clamping nut is applied to the nipple.

This arrangement has certain disadvantages, in view of the relativelytedious process involved in mounting the switch. Further, thearrangement is comparatively expensive.

It has been heretofore proposed to provide a mount which includes anannular series of spring fingers, insertable through the aperture of thesupporting panel in such a way as to detachably connect the switch tothe panel responsive to axial movement of the switch through theaperture.

However, in many instances, the construction of the snap-in mount hasbeen relatively complicated, particularly as regards its assembly withthe body of the switch. Often the switch housing must be speciallyformed, in a comparatively expensive manner, and in other instances, themount has had to be specially constructed. Then too, the assembly of themount with the switch body has often been complicated, involvingundesirably high labor costs.

The broad object of the present invention is to provide an improvedsnap-in mount characterized by its inexpensive design, and by aparticular cooperation of the same with the switch proper, to hold themount and switch body assembled without special fasteners, and withoutany connecting operation other than the relative axial movement of thebody and mount.

To this end, I provide a lip on the finger support ring of the mount,while on the wiring device I provide a cylindrical portion havingdiametrically opposed, longitudinal channels. The leads of the deviceare sheathed with insulation, as is usual, and seat in the channels.Normally, the leads would project outwardly from the channels beyond thediameter of the lip.

In accordance with the invention, the movement of the ring onto thecylindrical, longitudinally channeled portion effects a compression ofthe sheaths or coatings of the leads. This in turn causes the sheaths toexert a continual outward pressure against the finger support ring, atdiametrically opposed locations on said ring, when the ring is assembledwith the cylindrical portion.

In this way, I hold the snap-in mount assembled with the switch proper,entirely by a coactive relationship between the mount and theresiliently sheathed leads. This dispenses with connecting fasteners,attaching flanges, and equivalent expedients necessarily employed insnap-in mounts for electrical wiring devices as heretofore designed.

A further object is to provide a snap-in mount capable of formation froma single piece of inexpensive material, readily made to the desiredshape.

Still another object is to provide a snap-in mount which will involveminimum modification of the switch proper.

Another object is to provide a mount which, though inexpensively formed,will he possessed of a high degree of efiiciency as regards the grippingaction asserted thereby against the supporting panel.

Still another object of importance is to provide a mount which will bevisible to a minimum extent, when the switch is in its final, fully'installed position, thus to detract to a minimum degree from theattractive appearance of the installed switch.

Other objects will appear from the following description, the claimsappended thereto, and from the annexed drawing, in which like referencecharacters designate like FIGURE 3 is a sectional view substantially online- 3-3 ofFIGURE 2; and

FIGURE 4 is an exploded perspective view.

Referring to the drawing in detail, I have illustrated a rotary switchgenerally designated 10. The invention can be embodied in any of variouswiring devices, the switch being shown purely as one example. Since theinterior construction of the wiring device is relatively unimportant asfar as the present invention is concerned,

said interior construction need not be described, It is sufiicient tonote that the switch 10 would be mounted upon a supporting panel 12,which could be the instrument panel of an automobile, a wall of ahousing of an electrical appliance, etc. The panel has a circularopening 14 to accommodate the switch body.

In the illustrated example, the switch 10 has a body or housing 16, ofany suitable material, as for example a plastic having the desiredelectrically insulative qualities. The body 16 is formed with arearwardly projecting, cylindrical portion 18 the diameter of which isreduced relative to the main diameter of the body, whereby to define arearwardly facing, fiat, circumferential shoulder 20 at the juncture ofthe body 16 and the cylindrical portion 18. Formed in the cylindricalportion 18,

over the full length thereof, are diametrically opposed,

ings 26 of electrically insulative material. The outer di ameters of thesheaths are such as to cause the same to normally project radiallyoutwardly of the portion 18, beyond the channels 22. The coatings are ofa slightly resilient, compressible material, this being a characteristicof the coatings which plays an important part in the present invention.

Generally designated at 28 is a mount, formed from a single piece ofinexpensive sheet metal material readily blanked out and formed to thedesired end shape thereof illustrated in FIGURE 4. Quite possibly, I mayemploy a material other than sheet metal for the switch mount, such as amolded plastic.

The mount 28 is provided with a planiform base ring 30, defining a flatabutment surface adapted to bear against the correspondingly planarsurface of the rearwardly facing shoulder 20 (see FIGURE 3). The innerperiphery of the base ring 30 is of a diameter less thanv the diameterof body 16, and is integral with a rearwardly cylindrical portion 18.The inner diameter of lip 32,

however, is less than the distance measured diametrically Patented Oct.17, 1961 of the switch between the outermost points of projection of theuncompressed coatings or sheaths 26.

The mount 28, at the outer periphery of the base ring 30, is foldedonzitself as at 34, providing a finger support ring ift6linface to facecontact with the base ring 30*. The finger support ring 36 inturn mergesinto an annular Series of rearwardly projecting spring fingers '38. Thefingers 38 are uniformly, angularly spaced about the-circumfei'ence ofthe finger support ring, extending from the inner periphery of said ringso that the finger support ring will bear directly against the frontsurface of the supporting .panel 12. 1

The fingers 38 are formed with rearwardly diverging proximal portions40, merging at their divergent, rear extremities into rearwardlyconvergent distal portions 42.

Normally, the rear, divergent extremities of the proximal portions 4iwould lie upon a circle the diameter of which is greater than thediameter of the aperture 14. Accordingly, when the mount 28 is beingshifted rearwardly through the aperture 14, the divergent ends of theproximal portions 4% would engage the edge of the opening, and would becammingly biased radially inwardly, so as to pass-through the aperture14. When the divergent extremities of the proximal portions 40 havepassed through the aperture 14, they are again free to spring outwardlyto their normal positions, thus holding the mount assembled with thesupporting panel 12. In the final position, the finger support ring isin direct contact with the front surface of the panel 12,-as shown inFIGURE 3.

dnassembling the mount 28 with the switch 10, one merely extends theleads through the central opening of the mount, after which the mountand the switch body are relatively moved in an axial direction, towardeach other. As the mount moves onto the cylindrical portion 18, the lip32. presses'against the outwardly projecting portions of the insulatingsheaths or coatings 26, and said coatings are thus caused tobec'ompressed. Continued movement of the mount onto the cylindricalportion 18 of the switch body causes the lip 32 to press'the coatingsinwardly, with the coatings being held in their compressed conditions inthe finally assembled positions of the switch and mount. This is shownin FIGURE 3, and as will be observed, the snap-in mount, by compressingthe coatings 2'6, is thus assembled with the wiring device. Thecompressed coatings exert a pressure radially outwardly of theelectrical wiring" device, at diametrically opposed locations, againstthe-lip 32. A strong frictional engagement between the lip 32am theresiliently coated leads 24 is thus produced, whereby the mount 28 andthe wiring device are caused to be fully connected, through the mediumof the compressedleads interposed between lip 32 and cylindrical portion18.

It will be noted in this regard that rearwardly of lip 32, the sheathsremain uncompressed, bulging outwardly to define an abutment meansbehind the rear edge of the lip. Any tendency of the mount 28 to shiftrearwardly from its use position is thus effectively resisted, since theback edge of lip 32 would hang up on the uncompressed sheath portions asreadily seen from FIGURE 3. The shoulder and the uncompressed portionsof the sheaths respectivelylie directly in front of and rearwardly ofthe lip to define abutments. These limit the mount against both forwardand backward movement in respect to the switch body 16, in the eventthat a force tending to create such movement occurs. This is desirablesince such force might'otherwise overcome the resistance inherent in thefrictional interengagement of the sheaths with the mount and bodyrespectively.

-'With the mount and the wiring device so assembled, one merely movesthe device and its associated mount forwardly, to snap the mount intothe aperture 14, thus installing the switch upon the panel.

In this way, at minimum cost, I provide for inexpensive'swift, easyinstallation of wiring devices, utilizing a low cost mount inassociation with a wiring device having a minimum number of redesignedcomponents. The mount and the wiring device are at the same timecharacterized by the low cost of assembly with one another, in view ofthe use of the leads as friction grip means interposed between the mountand the wiringdevice to hold the same connected.

It is also very important to note that the construction permits mountingof electrical wiring devices on supports that are so designed as toprevent access to the back of the device, which access would be neededin the type using mounting nuts. Such an instance would occur when thesupport is a tube of relatively small diameter. Another instance wouldarise when the support, though flat, is so located as to prevent readyaccess to the back thereof.

t is believed apparent that the invention is not necessarily confined tothe specific use or uses thereof described above, since it may beutilized for any purpose to which it may be suited. Nor is the inventionto be necessarily limited to the specific construction illustrated anddescribed, since such construction is only intended to be illustrativeof the principles of operation and the means presently devised to carryout said principles, it being considered that the invention comprehendsany changes in construction that may be permitted within the scope ofpanel on which the wiring device is to be installed; and

at least one conductor Wire extending from the body and including anelectrically insulative sheath compressed between and frictionally boundagainst the ring and said cylindrical portion, to hold the fingersupport ring assembled with said cylindrical portion, said body andsheath abutting against the ring at locations spaced axially of thering, said ring being engaged by the body against movement axially ofsaid portion in one direction, the ring being engaged by the sheathagainst movement axially of said portion in the opposite direction.

2. In an electrical wiring device and mounting means of the snap-in typeintended for engagement in an aperture of a supporting panel, a wiringdevice body; a cylindrical portion extending rearwardly therefrom andreduced in diameter in respect to the body, whereby to define arearwardly facing shoulder on the body at the juncture of thecylindrical portion therewith; a finger support ring extending aboutsaid cylindrical portion adjacent said shoulder, the shoulder definingan abutment for locating the ring at the forward end of the cylindricalportion; an annular series of resilient, bowed fingers angularly spacedabout the cylindrical portion and projecting rearwardly from the ringalong said portion for snap fastener engagement with the edge of a panelaperture through which the cylindrical portion i extended; and at leastone conductor wire extending from the body and including an electricallyinsulative sheath compressed between and frictionally bound against thering and the said cylindrical portion to hold the finger support ringassembled with the cylindrical portion, said sheath comprising the solemeans holding the ring and cylindrical portion assembled with eachother, said shoulder and sheath being disposed as abutments in front andto the rear, respectively, of the ring, in positions limiting the ringagainst movement axially of said cylindrical portion in oppositedirections.

3. In an electrical wiring device and mounting means of the snap-in typeintended for engagement in an aperture of a support, a wiring devicebody; a rear portion thereon; rearwardly facing abutment means on thebody at the juncture of the same with said rear portion; a fingersupport ring extending about the rear portion, said abutment meanslimiting the ring against forward movement in respect to the body andrear portion; a plurality of spring fingers projecting from the ringrearwardly of said shoulder and resiliently bowed for snap fastenerengagement with the edge of the aperture of a support upon which thewiring device is to be installed; and at least one conductor wireextending from the body along the length of said rear portion andincluding an electrically insulative, resiliently compressible sheath,having a front part compressed between and frictionally bound againstthe ring and said rear portion, said sheath having a back part expandedin a direction radially outwardly from said rear portion and lying as anabutment limiting the ring against rearward movement in respect to saidbody and rear portion.

4. In an electrical wiring device and mounting means of the snap-in typeintended for engagement in an aperture of a support, a wiring devicebody having a back end formed with a rearwardly facing circumferentialshoulder; a rear portion rigid with the body and extending rearwardlyfrom said shoulder, said rear portion having angularly spacedlongitudinal channels extending from end to end of the rear portion, thebody having correspondingly angularly spaced apertures opening throughsaid shoulder into communication with the respective channels; a fingersupport ring extending about the rear portion in concentric relationtherewith, said ring lying in face-to-face contact with the shoulder,the shoulder limiting the ring against forward movement in respect tothe body and rear portion; an annular series of spring fingersconcentric with the body and projecting from the ring rearwardly of saidshoulder, said fingers being resiliently bowed outwardly for snapfastener engagement with the edge of the aperture of a support on whichthe device is to be installed; and a pair of conductor wires extendingthrough the respective apertures of the body, said wires havingelectrically insulative, resiliently compressible sheaths engaged in therespective channels, said sheaths having front parts compressed withinthe channels and frictionally interengaged with the ring and said rearportion, the sheaths having back parts expanded in a direction radiallyoutwardly from the rear portion and projecting out of the channels asabutments in the path of axial movement of the ring, said abutmentslimiting the ring against rearward movement in respect to said body andrear portion.

5. In an electrical wiring device and mounting means of the snap-in typeintended for engagement in an aperture of a support, a wiring devicebody having a back end formed with a rearwardly facing, circularlyshaped, circumferential shoulder; a cylindrical rear portion of circularcross-section integral with and projecting rearwardly from said shoulderin concentric relation therewith, the rear portion having a pair ofdiametrically opposed longitudinal channels of part-circularcross-section extending from end to end of the rear portion, the bodyhaving correspondingly diametrically opposed apertures opening throughsaid shoulder into communication with the respective channels; a mountincluding a finger support ring extending about the rear portion inconcentric relation therewith and with the shoulder, said ring having afiat abutment surface lying in face-to-face contact with the shoulder tolimit the ring against forward movement in respect to the body and rearportion, an annular lip integral with the ring and projecting rearwardlytherefrom, said lip extending about the rear portion in close proximitythereto and terminating forwardly of the back end of the rear portion toexpose a part of the length of the rear portion, and an annular seriesof spring fingers also integral with the base ring and projectingrearwardly therefrom, said series being concentric with and extendingabout the lip with the fingers of the series bowed resiliently outwardlyfor snap fastener engagement with the edge of the aperture of a supporton which the device is to be installed; and a pair of conductor wiresextending through the respective apertures of the body, said wireshaving electrically insulative, resiliently compressible sheaths ofcircular cross-section engaged in and projecting outwardly from therespective channels, the sheaths having front parts compressed withinthe channels and frictionally interengaged with the ring and said rearportion, the sheaths having back parts expanded in a direction radiallyoutwardly from the exposed part of the rear portion in position lying asabutments effective to limit the ring against rearward movement inrespect to the body and rear portion.

References Cited in the file of this patent UNITED STATES PATENTS1,376,068 Benjamin Apr. 26, 1921 1,916,194 Godley July 4, 1933 2,353,778Mattis July 18, 1944 2,762,989 Johnson Sept. 11, 1956

